The present invention relates to electrical connectors and more particularly to a shielding arrangement for such connectors.
Shielded connectors having a shield member surrounding the housing and protecting signals from ambient electromagnetic noise are known. During mating of such connectors, the shield members generally contact each other to establish a common potential between them.
Known examples in the prior art include shielded connectors that have a plurality of contacts in a housing surrounded by a single shield member. The single shield member typically has an opening at an end into which the shield member of a mating shielded connector is inserted. Another known shielding arrangement places projections on the inner circumference of an opening in shield members for engaging the mating shielded connector is inserted to achieve point contact at a plurality of locations on the shield member of the mating shielded connector (see Utility Model HEI 1-38866). These projections serve to fasten the engaged shield members which is thought to increase the reliability of the electrical contact between them.
With the ongoing development of computer technology comes a need for greater signal density through such connectors as well as the need for increasing signal transfer rates. As the size of these multi-contact connectors increases the openings that receive the complementary shield member increase accordingly. After repeated mating cycles these large openings tend to stretch because of the outward force applied by the projections described above. The result is that movement occurs between the mated connectors causing intermittent electrical contact at the signal and/or shielding connections.
The intermittent contact along the shield member may only occur at certain locations along the opening. This causes current to pass over the shield at the contacting sections and to be blocked at those sections with poor or no contact thus reducing the electromagnetic interference protection. In applications where the shield is grounded, the ground path will become long due to detours of the conduction path caused by the poor or non contacting sections, which may affect the fall of pulse signals and impede high-speed signal transmission.
The object of this invention is to provide a shielded connector arrangement having improved electrical contact between the shield members of mated connectors.
This and other objects are achieved by providing a shielded connector that has a plurality of signal contacts and a shielding shell that engages a mating connector. The shielding shell being equipped with a conductive inner shell which receives the mating connector is inserted and an outer shell that supports the inner shell. The outer shell serves to prevent the inner shell from expanding due to the insertion of the mating connector.